Serum/plasma isolator cup

ABSTRACT

A cup to hold the serum or plasma (fluid portion) separated from the cells after blood drawn from a patient has been placed into a sample tube and centrifuged. The blood may be drawn directly from the patient into the sample tube or may be transferred into the tube after being drawn from the patient by other means. The cup containing the fluid portion is inserted in the said tube containing the cells and snapped into place, thus isolating the fluid portion from the cells but retaining it in the tube identified with the patient. Such cup has a base which is rounded or of a form that will not be free standing, the purpose being to insure that it will only be placed in the open end of the tube to alleviate the danger of confusion of samples. The cup base is also designed to serve as a cap for another cup.

[ Apr. 30, 1974 SERUM/PLASMA ISOLATOR CUP Inventors: Thomas N. Note,Jr., Wayne; Evelyn J. Walker, Hackensack, both of NJ.

Assignee: Becton, Dickinson and Company,

Rutherford, NJ.

3,677,435 7/1972 Davis 220/97 C X FOREIGN PATENTS OR APPLICATIONS192,785 11/1957 Austria 220/42 B Primary Examiner-loseph ScovronekAttorney, Agent, or Firm-Kane, Dalsimer, Kane, Sul- [22] Flled. Apr. 15,1971 livan & Kurucz 21 Appl. No.: 134,148

[57] TRACT U-S- Cl. B, A cup to the erum or plasma portion) sep- 220/9 Carated from the cells after blood drawn from a patient B011 B65d 21/02,Golf! 16 has been placed into a sample tube and centrifuged. 1 Field ofSearch 3/230, 230 B, 253, 259, The blood may be drawn directly from thepatient into 3/2 2 3- 2 97 the sample tube or may be transferred intothe tube 195/139 206/65 84 after being drawn from the patient by othermeans. The cup containing the fluid portion is inserted in theReferelwes Cited said tube containing the cells and snapped into place,

UNITED STATES PATENTS thus isolating the fluid portion from the cellsbut re- 3,540,s57 11/1970 Martin 23/292 mining it the tube identifiedwith the Patiehh Such 3,554,705 1 1971 Johnston 23 292 P has a baseWhich is rounded 0r of a form that Will 3,072,362 1/1963 Allen 23 292not be free standing, the p p being to insure that 3,625,654 12/1971 VanDuyne... 23/292 it will only be placed in the open end of the tube to ,83/1909 E kart 22 B X alleviate the danger of confusion of samples. Thecup 3/1934 McDowell 220/42 B base is also designed to serve as a cap foranother cup. 3,396,868 8/1968 Fitzgerald 220/97 C 3,520,441 7 1970Fitzgerald 220/97 c x 4 Claims, 4 Drawing Figures 4 v 1 1 5 t 4 f I /flf f 1 SERUM/PLASMA ISOLATOR CUlP' BACKGROUND OF THE INVENTION It isuniversally accepted in the chemistry laboratory that serum or plasma(herein referred to as the fluid portion) should be separated frompacked cells as soon as possible after blood has been drawn from apatient. However, many laboratories do not follow this practice and, inthe interest of retaining sample identity or expediting and simplifyingprocedure, centrifuge the sample in its original tube and retain thefluid portion and cells together until the desired laboratory work canbe performed.

This problem has been overcome by the isolator cup of the presentinvention which permits the fluid portion to be removed from intimatecontact with the cells and placed in the cup as soon as possible aftercentrifuging. The cup containing the fluid portion is then placed in theopen end of the original tube and snapped down into place, thusretaining the fluid portion and the cells together as a unit butnevertheless separated from each other. Such unit keeps its originalidentification.

SUMMARY OF THE INVENTION It is an object of this invention to provide acup which isolates the fluid portion from the cells of a blood sampleplaced in a sample tube, but permits the cup and the original tube to becombined into a unit for retention of sample identity and convenience ofhandling (processing) in an analytical system.

It is a further object to provide an isolator cup which can be insertedinto the open end of a blood sample tube with the open end of the cuplocking positively into the open end of the tube to seal such tube.

It is a further object to provide a cup which isolates a first portionof a mixture separated from a second portion of the mixture in a sampletube, the cup holding the first portion being combined with the sampletube holding the second portion into a unit for retention of sampleidentity.

It is a further object to provide an isolator cup with a base which isrounded or shaped to serve as a cap for another cup, but will not befree standing for the purpose of insuring that it will only be placed inthe open end of a tube to alleviate the danger of confusion of bloodsamples. v

It is a further object to provide an isolator cup which is simple,inexpensive to manufacture, and lends itself to color coding foridentification.

It is a further object to provide an isolator cup which can be used forstandards and controls and affords potential savings due to reducedvolume of comparatively expensive materials used in automatic testingmachines.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages willbecome apparent from the following description which is to be taken inconjunction with the accompanying drawings, in which FIG. 1 is aperspective view of the isolator cup of the present invention;

FIG. 2 is a sectional view of a blood sample tube with the isolator cupinserted in the open end of the tube; and

FIG. 3 is a sectional view of several isolator cups stacked up with thebottom of one cup serving as a cap for the cup below it.

FIG. 4 is a sectional view of the cup being inserted into the open endof a blood sample tube to show the taper of the upper wall portion ofthe cup providing the pressfit of the cup into the tube.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, thereis shown in PEG. 1 an empty isolator cup 10 having a round base 11 andan open top end with a lip 12 running around the top. The cup is adaptedto fit into the open end of a conventional blood sample tube I3 (FIG.2). Running around the wall at different levels are lines 14 to indicatevarious volume fill levels in the cup.

The cup is molded in clear or translucent plastic and lends itself tocolor coding to provide identification for routing of the sample todifferent areas of the laboratory or to indicate types of samples. Thinwalled polyethylene has been found adequate for such a cup and providesa sufficient degree of clarity. The bottom wall of the cup has a slighttaper inwardly and the design of the cup base is round, as illustrated,or some similar contour which will insure that it will not be freestanding. It is thus intended that, after receiving the fluid portion,it will be placed down in the open end of the tube from which the fluidportion came. This alleviates the danger of confusion of samples. Thecup base is so designed that it can serve as a cap for another cup (FIG.3). Thus the fluid portion in the cup can be so capped when the fluidportion is being stored for a period of time. It is also possible topile several of these cups on top of each other with the base of one cupserving as a cap for the cup below it (FIG. 3). The bottom cup can beinserted in a sample tube as shown in FIG. 2.

The cup can be made in various diameters to conform to the diameters ofthe available blood sample tubes. Such diameters at the open ends musteach have sufficient tolerance to accommodate wide variations in theinside diameters of the tube at the open ends, but the open endof eachcup must lock positively into place in the open end of the tube.

The following procedure for use of such a cup might be considered astypical. A prenumbered blood sample tube is brought to the patient. Theblood sample is drawn and at that time the tube number is positivelyrelated to the patient. The sample is brought to the laboratory where,after logging in, it is permitted in the case of serum to stand untilproper clot formation has occurred. In the case of plasma it will not benecessary for the sample to stand for clotting. The sample is thenplaced in a centrifuge, together with other similar tubes, and the bloodis separated with the cells in the bottom portion of the tube and clearfluid portion up above. As soon as possible after spinning, the fluidportion is removed from intimate contact with the cells and placed inthe isolator cup. The cup is then inserted in the open end of theoriginal tube and snapped down into place. Thus the fluid portion isstill in the original tube that was identified with the patient but thefluid portion is no longer in contact with the cells which could bringabout deterioration after a period of time. As used herein the termblood sample tube shall apply either to a blood collecting tube intowhich blood is drawn directly from the patient or to a tube into whichblood is transferred after the blood is drawn from a patient by syringeor other means.

While this invention has particular use for blood testing, it will beunderstood that it may also be used where one portion of a mixture hasbeen separated from a second portion of the mixture and it is necessaryor desirable to keep the two portions together as a unit foridentification but separated from each other. in such case the upperportion is removed from the top of the lower portion of the mixture inthe sample tube. Such upper portion is placed in an isolator cup whichis then inserted into the sample tube holding the other portion of themixture.

For blood testing, the invention can be used as heretofore described. inusing automatic chemistry analyzers a large volume of comparativelyexpensive standards and controls would be required to fill conventionalsample tubes. If the cups of the present invention are used a smallervolume of these comparatively expensive liquids will be required. Thecup holding such liquid is inserted into the top of a sample tube whichis empty but serves as the means of identification for the liquid.

Thus the aforementioned objects are most effectively obtained. Althoughthe preferred embodiments of the invention have been disclosed anddescribed in detail herein, it should be understood that this inventionis in no sense limited thereby and its scope is to be determined by thatof the appended claims.

Having thus described the invention, what is claimed l. A cup incombination with a sample tube forming an integral unit useful forseparately storing whole blood, serum or plasma or cells and forhandling these in an analytical system designed to place the fluidportion in the cup and the cells in the tube, said cup being made ofthin walled plastic and comprising a cylindrical tubular section, anopen top end with a lip extending around such top end and a closedbottom end which is curved so as not to be free-standing, the outersurface of the tubular section conforming in size and shape to theinside of the top of the sample tube, the upper wall of the said cupbelow the said lip having a tapered surface adapted to contact and forma press fit with the upper inner wall of the said sample tube, the saidcup containing a first portion separated from the sample being insertedand press fitted into the top of the sample tube containing a secondportion of the sample with the top lip of the cup resting on the top ofthe sample tube to form an integral unit with the portions isolated fromeach other and identifiable as belonging to a specific patient from whomthe sample was taken.

2. The combination of claim 1 wherein the outer surface of the lower endof the tubular section of the cup has a slight taper inwardly andconforms in shape to the inner tapered surface of the said cup, wherebythe lower end of the said cup can be press fit into the open end of anyother like cup.

3. A method for retaining together, but isolated from each other, thefluid portion and the cells of a blood sample comprising placing a bloodsample drawn from a patient in a sample tube; separating the fluidportion and the cells into layers with the cells at the bottom and thefluid portion above; removing the fluid portion from the tube andplacing it into an isolator cup made of thin walled plastic and having acylindrical tubular section, an open top end with a lip extending aroundsuch top end and a closed bottom end which is curved so as not to befree-standing, the outer surface of the tubular section conforming insize and shape to the inside of the top of the sample tube, the upperwall of the said cup below the said lip having a tapered surface adaptedto contact and form a press fit with the upper inner wall of the saidsample tube; and inserting the isolator cup containing the fluid portioninto the top of the sample tube containing the cells with the cupresting on its top lip within said sample tube and the tops of the cupand tube press fit together to form an integral unit for handling in ananalytical system designed to process the sample and to identify theunit as belonging to a specific patient from whom the sample was taken.

4. The method of claim 3 in which the said first isolator cup is cappedwith a second isolator cup similar to the first cup to preventevaporation of the fluid portion of the first cup, the outer surface ofthe lower end of the tubular section of the second cup having a slighttaper inwardly and conforming in shape to the open end of the first cup.

2. The combination of claim 1 wherein the outer surface of the lower endof the tubular section of the cup has a slight taper inwardly andconforms in shape to the inner tapered surface of the said cup, wherebythe lower end of the said cup can be press fit into the open end of anyother like cup.
 3. A method for retaining together, but isolated fromeach other, the fluid portion and the cells of a blood sample comprisingplacing a blood sample drawn from a patient in a sample tube; separatingthe fluid portion and the cells into layers with the cells at the bottomand the fluid portion above; removing the fluid portion from the tubeand placing it into an isolator cup made of thin walled plastic andhaving a cylindrical tubular section, an open top end with a lipextending around such top end and a closed bottom end which is curved soas not to be free-standing, the outer surface of the tubular sectionconforming in size and shape to the inside of the top of the sampletube, the upper wall of the said cup below the said lip having a taperedsurface adapted to contact and form a press fit with the upper innerwall of the said sample tube; and inserting the isolator cup containingthe fluid portion into the top of the sample tube containing the cellswith the cup resting on its top lip within said sample tube and the topsof the cup and tube press fit together to form an integral unit forhandling in an analytical system designed to process the sample and toidentify the unit as belonging to a specific patient from whom thesample was taken.
 4. The method of claim 3 in which the said firstisolator cup is capped with a second isolator cup similar to the firstcup to prevent evaporation of the fluid portion of the first cup, theouter surface of the lower end of the tubular section of the second cuphaving a slight taper inwardly and conforming in shape to the open endof the first cup.